I used the foil insulation under my carpet and firewall(summit or any T-Bird supplier can get you the stuff) and it really cut down on the heat and noise. However, while it cut down on the heat, it did not eliminate it. It still gets a little uncomfortable in bumper to bumper traffic in Atlanta in the summer.
You may want to try a product that should be the "ultimate" in heat protection for the interior. It is expensive, but they already make an 8-piece pre-cut kit just for the thunderbird. The web site is
www.koolmat.com, look under "new products" for the T-bird listing and prices. This stuff is only 1/10 of an inch wide, but should work better than the foil (if you can believe what's posted). If anyone uses this stuff, let me know, as I'm going to do a body-off, and might want to upgrade my heat protection in the cockpit.
Thanks,
Mike McNamee
1957 Starmist "Nadine"
Roswell, GA